1. Field of the Invention
The present invention relates to a transparent electrode pattern structure and a touch screen panel including the same, and more specifically, to a transparent electrode pattern structure with low visibility to a user and a touch screen panel including the transparent electrode pattern structure.
2. Description of the Related Art
Commonly, a touch screen is a screen equipped with a special input device to receive position signals input by touching a screen with a finger of a user or a stylus pen. Such a touch screen does not use a keyboard but has a configuration of multi-layer laminates wherein, when the finger of the user or an object such as a stylus pen touches a specific character or position displayed on the screen, the touch screen identifies the position and directly receives data through a screen picture, in order to practically process information at a specific position by a software stored therein.
In order to recognize the touched position without degrading the visibility of an image displayed on the screen, it is necessary to use a transparent electrode. Generally, the transparent electrode having a predetermined pattern formed thereon is used.
As a transparent electrode used in a touch screen panel, various structures are known in the related art. For example, a glass-ITO film-ITO film (GFF), a glass-ITO film (G1F), or a glass only (G2) structure is used in the touch screen panel.
Among these, the GFF is a most commonly used structure and includes two transparent electrodes (indium tin oxide, ITO) formed with two films required to implement X-axes and Y-axes. The GIF includes a first ITO thin film deposited on a rear surface of a glass and uses a film as a second ITO film similarly to a convention method. G2 is a structure formed by a method depositing and pattering an ITO thin film for an X-axis on a rear surface of one reinforced glass, forming an insulation layer thereon, and pattering another ITO thin film for a Y-axis. Transmittance in the GFF, G1F, and G2 is increased while the power consumption is reduced in this order, therefore studies for the G2 structure are actively conducted.
However, in the G2 structure which uses the patterned transparent electrode, a patterned portion and a non-patterned portion (pattern opening) of the transparent electrode may be visually distinct from each other. Accordingly, bigger a difference in reflectance between the patterned portion and the non-patterned portion the reflectance difference clearly appears, therefore, the visibility of the appearance as a display element is decreased. In particular, in a capacitive-type touch panel, since the patterned transparent electrode is formed on the entire surface of the display unit of the display, even if patterning the transparent electrode layer, the display element needs to have a good appearance.
In order to improve such a problem, for example, Japanese Patent Laid-open Publication No. 2008-98169 discloses a transparent conductive film in which an under coat layer including two layers with different refractive indexes is formed between a transparent substrate and a transparent conductive layer. In addition, as an embodiment of thereof, the above-described patent further discloses a transparent conductive file in which a silicon-tin oxide layer having a refractive index of 1.7 as a high refractive index layer (with a thickness of 10 nm or more), a silicon oxide layer having a refractive index of 1.43 as a low refractive index layer (with a thickness of 30 nm), and an ITO film having a refractive index of 1.95 as a transparent conductive layer (with a thickness of 15 nm) are sequentially formed in this order.
However, since a difference between the patterned portion and the non-patterned portion is clearly appeared in the transparent conductive film disclosed in the above-described patent, it is still insufficient to improve the appearance of the display element. Further, when the transparent conductive film further includes a transparent dielectric layer such as a silicon-tin oxide layer or a silicon oxide layer, it is difficult to implement a thin film structure.